Motorola Corporation

James Joseph Kosmach

Stephen N Levine

Cheung Auyeung

Jeffrey C Smolinske

Louis D Finkelstein

Howard E Levin

Frederic Fontaine

Jaksa Djordjevic

Stephen Norman Levine

A receiver includes a detector and a decoder. The detector is adapted to demodulate a received signal to generate a received word. The received word includes a plurality of symbols, and each symbol contains data associated with a first phase and data associated with a second phase. The detector is further adapted to generate a plurality of energy values relating each received symbol to one of a plurality of potential symbols. The decoder is adapted to generate a first set of bit metrics based on the energy values in response to the receiver being assigned to the first phase and a second set of bit metrics based on the energy values in response to the receiver being assigned to the second phase. The decoder is further adapted to identify the least reliable bits in the received word based on one of the first and second sets of bit metrics.

Method and apparatus for assigning bit metrics for soft decision decoding

Coding gain is used to configure a communication system using a programmable error correction scheme. A best available error correction configuration is selected from among several configurations to provide an optimal coding gain performance for a given line or set of line characteristics and a given communication system. Payload is calculated for each of several error correction configurations, and the configuration providing the highest payload for a target bit error rate is selected. Use of gross gain to configure the communication system further provides an optimal configuration.

Method of identifying an improved configuration for a communication system using coding gain and an apparatus therefor

A method and apparatus decodes a data packet in a communication system utilizing an error correcting code. Channel symbols are received (302), and channel symbol reliability weights are determined (306) for each. A code word symbol is formed (308) from the channel symbols, and the channel symbol reliability weights are mapped (312) into a code word symbol reliability weight, which is set equal to the minimum channel symbol reliability weight mapped for the code word symbol. The method and apparatus continues (318) to similarly process additional channel symbols until the data packet is completely collected. Then, a predetermined number of code word symbols having the lowest code word symbol reliability weights in the data packet are marked (320) as erasures, after which the data packet is decoded (322) by utilizing a soft decision decoding technique.

Method and apparatus for decoding a data packet

The present invention is method, rate controller, and system for preventing overflow and underflow of a decoder buffer in a video compression system. First, a plurality of quantized video bits is received from an encoder (102). The plurality of quantized video bits correspond to a video frame type. Then, a virtual buffer is created, in a rate controller, to model fullness of a decoder buffer, based on the quantized video bits, to produce a virtual buffer fullness (104). A quantization stepsize estimate is finally determined, in a rate controller, based on at least a first predetermined target bit allocation, the video frame type, and the virtual buffer fullness (106). The quantization step size estimate will prevent the overflow and underflow of a decoder buffer.

Method, rate controller, and system for preventing overflow and

The present invention provides a method (100) and device (200) for allocating bits to video pictures in a video compression system. A sequence of video frames or pictures is received, and the number of bits used to compress a previously encoded frame and a signal-to-noise ratio for the immediately previously encoded video frame are determined. Rate distortion model parameters are updated. Then, first, second, and third deviations are determined. Finally, the bit allocation for the frame is determined based on the first number of bits used to compress a previously encoded frame, the first deviation, the second deviation, and the third deviation.

Method and device for determining bit allocation in a video compression

A method and apparatus for providing cryptographic protection of a data stream are described in accordance with the Open Systems Interconnection (OSI) model for a communication system. This cryptographic protection is accomplished on the transmitting side by assigning a packet sequence number to a packet derived from a data stream received from a network layer. Subsequently, a transmit overflow sequence number is updated as a function of the packet sequence number. Then, prior to communicating the packet and the packet sequence number on a physical layer, the packet is encrypted as a function of the packet sequence number and the transmit overflow sequence number. On the receiving side, the packet sequence number is extracted from the physical layer. In addition, a receive overflow sequence number is updated as a function of the packet sequence number. Finally, the encrypted packet is decrypted as a function of the packet sequence number and the receive overflow sequence number. In addition, a transmitting and a receiving communication unit for use in a communication system which includes cryptographic protection of a data stream is described.

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Atlanta, GA, United States of America

James Joseph Kosmach